DukeNukemForever: If you are into that type of games, of course he should give it a try. But my impression is that he is looking for really impressive looking games. In my eyes many of the 3dfx games still look very interesting today, as they have a special style to me. Like pixel-art the graphics are maybe old, but they have also a comic look that let you still today enjoy the graphics. They are colourful and smooth, soft light and not really edgy. To me the first Tomb Raider never looked like that, the 3dfx version is still very grayish/brownish and edgy. It's really a question of taste I guess.
Well, it is one of the earliest 3Dfx Glide games so it might be later games had improved support...
...but having said that, I personally didn't find it that 3Dfx (Voodoo) games would have become considerably better later on. After all the 3Dfx cards were pretty dumb cards, they could only smooth out the graphics output somewhat (texture filtering, perspective corrected textures, alpha blending (=transparency effects) etc.), they didn't e.g. help increasing the polygon count of 3D models as those were still calculated by the CPU, while nowadays 3D cards have a dedicated GPU for that, allowing higher polygon counts.
Some of the things I like in Tomb Raider graphics even today are also e.g. its top-notch animation (at least for Lara itself), which in itself didn't have much to do with the used graphics card I guess. 3Dfx Glide support just made sure that there were none of those irritating floating and twisting textures while you moved around, textures were smoothed out, the water surface had transparency effects, and of course that you could run it in a higher 640x480 resolution at a good speed. Artifacts that you'd see if running the Playstation version, or the PC VGA version (without 3D support).
One thing to keep in mind though is that "3Dfx support" in games can mean either for the early Voodoo era cards, or Voodoo 2. The latter, IIRC, had more frame buffer memory so its games could be run also in the 800x600 resolution, not only 640x480. Not sure if some Voodoo 2 games also had better textures as it had more memory for textures too. The increased resolution (for Voodoo 2 cards) might be why you feel later 3Dfx games weren't as "edgy" (jaggy?). 3Dfx cards didn't support edge antialiasing so at least it shouldn't be about that...